See also: How do I search for a function?



PDL::Delta - PDL changes between V1.0 and V2.0


This file is an attempt to list the major user-visible changes between PDL versions 1.0 and 2.0.

Core Changes

Piddles are not hashes any more:

    $a = zeroes 10,10;
    $$a{FOO} = "bar"

doesn't work. They are currently scalar references (to opaque C structures in finer terms) because of speed as well as syntactic issues. If you want to have a hash, use


which returns a reference to an anonymous hash. Also, subclassing works if you store a piddle in the hash member ``PDL''.

There are also many core enhancements to support Dataflow and Slicing tricks, but these do not introduce any incompatibilities.

Incompatible Changes vs 1.11


Order of the arguments has changed.

copy method

No longer copies the header. This may not be a misfeature.

Documentation Changes

Many of the base and library pods were updated.


The Changes file for exhaustive details on what changed.

The INSTALL file for how to build PDL.

The README file for general stuff.


pdldelta was inspired by perldelta man page in the Perl 5.004 distribution.